Tornado is Vulnerable to Quadratic DoS via Repeated Header Coalescing
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| tornadoweb | tornado | affected |
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No data.
| Vendor | Product | Versions |
|---|---|---|
| Tornadoweb | Tornado | — |
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4461-1 | python-tornado security update |
Debian DSA |
DSA-6195-1 | python-tornado security update |
Github GHSA |
GHSA-c98p-7wgm-6p64 | Tornado: Quadratic DoS via Repeated Header Coalescing |
Ubuntu USN |
USN-7950-1 | Tornado vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.599% probability within 30 days)
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:* |
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Tornadoweb
Tornadoweb tornado |
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| Vendors & Products |
Tornadoweb
Tornadoweb tornado |
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
threat_severity
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| Type | Values Removed | Values Added |
|---|---|---|
| Description | Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a single maliciously crafted HTTP request can block the server's event loop for an extended period, caused by the HTTPHeaders.add method. The function accumulates values using string concatenation when the same header name is repeated, causing a Denial of Service (DoS). Due to Python string immutability, each concatenation copies the entire string, resulting in O(n²) time complexity. The severity can vary from high if max_header_size has been increased from its default, to low if it has its default value of 64KB. This issue is fixed in version 6.5.3. | |
| Title | Tornado is Vulnerable to Quadratic DoS via Repeated Header Coalescing | |
| Weaknesses | CWE-400 | |
| References |
| |
| Metrics |
cvssV3_1
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